Locking device



Nov. 10, 1964 J. DRAZICK 3,155,479

LOCKING DEVICE Filed April 5, 1963 INVENTOR.

JON/V ORAZ/CK United States Patent M 3,156,479 LOCKING DEVICE JohnDrazick, 8565 Steel Ave., Detroit 28, Mich. Filed Apr. 5, 1963, Ser. No.270,936 3 Claims. (Cl. 279-76) This invention relates to an improvementin a holding device and has particularly to do with toolholdersutilizing a spring pressed detent to retain a tool in its socket.

These tools are used extensively for holding dies and punches in a diebed. It is important in these construction that it be easy to releasethese dies for replacement or for changing a particular set-up.

It is also important that the die be securely held against rotation inits particular socket and that it be solidly retained against removalfrom the stripping forces which are frequently present in the operationof a die of this kind. This invention contemplates an improvement overthe structure disclosed in my US. Patent No. 2,969,243, dated January24, 1961.

More specifically, in the previous disclosure, the holding device in theform of a plunger was so arranged that it had an actual point contactwith the socket of the shaft being held. In View of the frequentapplication of the stripping forces and sometimes the tendency for thesedevices to rotate, it is desirable that there be more of an area contactbetween the plunger device and the wall of the recess in the shank ofthe tool.

In the present device, I have accomplished this by providing a detentdevice shaped to lie in contact over a considerable area of the holderrecess in such a manner that forces transmitted to this area areabsorbed through the detent to the body of the holding structure.

Other objects and features of the invention relating to details ofconstruction and operation will be apparent in the following descriptionand claims.

Drawings accompany the disclosure and the Various "iews thereof may bebriefly described as:

FIGURE 1, a sectional view showing the general assembly of the devicewith the locking plunger and the body portion in section.

FIGURE 2, an enlarged view showing specifically the plunger and itsrelationship to the retaining body and the tool body.

FIGURES 3, 4, and 5, progressive sectional views on lines 33, 4-4 and5-5 of FIGURE 2.

In FIGURE 1, the particular die bed, which is shown for purposes ofillustration, comprises a hardened bottom plate It with a body plate 12,this body plate being screwed to the bottom plate and having a pluralityof holes, one of which is shown at 14 designed to receive the shank 16of a tool. Within the plates and 12 is an angled hole 13 which bottomsat 20, there being a compression coil spring 22 in this hole whichpresses outwardly against the detent or plunger 24. The plunger has aslot 26 defined by chordal walls 28 and 30 on the one hand and spacedparallel planes 31 parallel to the axis of the plunger on the otherhand. The plunger is retained by a pin 32 which acts on the wall 30 andis retained in a hole 34 by a screw retainer 36 which has a hole 38, themargins of which retain the head of the pin 32.

The hole 38 permits access to the pin wherein a downward force willdepress the plunger 24 out of the intersection with the tool 16. In thewall of the tool shank 16 is a recess 42 which is formed by acylindrical end mill which is run into the wall of the shank 16 at aboutat 5 angle to the general angle of the plunger hole 18 (see FIGURE 1).This angle is preferably within the range of 3 to 10 and is preferablywhat is called a locking angle with respect to mutual wedging surfaces.

It will be noticed that the snub-nosed plunger 24 is provided with aclearance at 44 so that it does not contact the 3,155,479 Patented Nov.10, 1964 2 walls of the recess 42. A portion of the side Wall of theplunger 24, however, opposite the slot 26, is shaped in a taperedsurface illustrated in FIGURE 2 at 50. FIG- URES 3, 4 and 5 show thistaper and the point of blending with the major circle of the plunger.

In FIGURE 3, the taper surface 50 blends at 52 to the major circle ofthe plunger and the tapered surface is formed circularly about an axiscenter 54. In FIGURE 4, the tapered surface 50 has blending points 56 alittle closer to the center line and this surface is formed around acenter 58. In FIGURE 5, the surface 50 has a blending point at 60 quiteclose to the center line and is formed around a center 62. Thisstraight-walled partialcylinder surface is preferably formed at the 5angle from the major axis of the plunger so that it will match with thesurface of the recess 42 in the area indicated at 64.

Thus, as shown in FIGURE 2, between the section lines 3-3 and 5-5 andextending a little beyond on each side, the surface 50 isstraight-walled tapered surface circular in cross section so that theplunger can actually have a wedging action against the wall of therecess 42.

The plunger is operated, of course, by inserting a punch member throughthe hole 38 to apply pressure to the head 4% of the pin 32, thusdepressing the plunger against the spring 22.

When the shank of a punch or tool 16 is inserted into the hole 14, itwill depress the plunger against the spring and then as the shankreaches its home position, the plunger will snap back through the actionof the spring into contact With the wedge surface 64 of recess 42 over awide area.

It will be seen that the so-called stripping forces, that is, forceswhich would tend to pull the shank 16 out of the hole 14, aretransmitted to the plunger throughout the entire circumferential surface50 which is axially in contact at 64 then up to the solid wall contactof the plunger with the recess 18 in the area indicated generally at 66.Thus, there is a solid cylindrical contact with the area 50-64 on theone hand and a solid cylindrical contact in the area 66 so thatstripping forces are solidly met by a tight plunger with a wide wallsurface contact on both sides. This is frequently very important where apunch is not circular.

While the device is disclosed in connection with the retention of acylindrical shank 16, it will be appreciated that it could be utilizedfor the retention of other elements of different cross section as longas the recess in the element to be held is provided with the suitablemating surface.

I claim:

1. A releasable holding device for retaining recessed elements in aretaining recess in which a releasable resiliently biased plungerengages a recess in the element to be retained and in which the plungeris inserted into an angled bore intersecting the retaining recess, thatimprovement which comprises a basically cylindrical plunger movableaxially in a cylindrical bore, having one wall adapted to matchcomplementally the cylindrical wall of the bore and having an oppositewall formed as a cylinder on an axis angled to the axis of said plungerand said bore, said angle increasing away from the bore and acomplemental cylindrical angled wall in the recess of the element to beretained also disposed at an angle to the plunger angle similar to thatof the opposite wall of said plunger wherein the two angled walls willwedge together as the plunger moves into the recess in the retainedelement providing a relatively large area of contact circumferentiallyand axially for transmitting dislodging forces through said plunger tothe opposite wall of said bore.

2. In a releasable holding device for retaining recessed elements in aretaining recess in which a releasable resiliently biased plungerengages a locking recess in the element to be retained and in which theplunger is inserted into an angle bore intersecting the retainingrecess, an improved tool shank to serve as the retained element, saidtool shank having a shape to fit complementally into a retaining recessinto which it is to be retained and having a locking recess formed inone wall thereof by the removal of stock, said locking recess having acylindrical shape angled to the axis of the element to serve as awedging surface for a retaining plunger wherein dislodging forcesexerted on said element can be transmitted through said wedging surface.

3. A releasable holding device for retaining recessed elements in aretaining recess in which a releasable, resiliently-biased plungerengages a recess in the element to be retained and in which the plungeris inserted into an angled bore intersecting the retaining recess, thatimprovement which comprises:

(a) a basically cylindrical plunger movable axially in a cylindricalbore, having one wall adapted to 20 match complementally the cylindricalwall of the bore and having an opposite wall extending substantiallyapproximately 180 around said plunger formed as a cylinder on an axisangled in the range of 3 to 10 to the axis of said plunger and saidbore, said angle increasing away from the bore, and

(b) a complemental cylindrical angled wall in the recess of the elementsto be retained also disposed at an angle to the plunger similar to thatof the opposite wall of said plunger wherein the tWo angled Walls willWedge together as the plunger moves into the recess in the retainedelement providing a large area of contact circumferentially and axiallyfor transmitting dislodging forces through said plunger to the oppositewall of said bore.

References Cited by the Examiner UNITED STATES PATENTS 2,128,116 s/ssBoone 27976 2,138,253 11/38 Lynch 27976 2,969,243 1/61 Drazick 27976FRANK SUSKO, Primary Examiner.

ROBERT C. RIORDON, Examiner.

1. A RELEASABLE HOLDING DEVICE FOR RETAINING RECESSED ELEMENTS IN ARETAINING RECESS IN WHICH A RELEASABLE RESILIENTLY BIASED PLUNGERENGAGES A RECESS IN THE ELEMENT TO BE RETAINED AND IN WHICH THE PLUNGERIS INSERTED INTO AN ANGLED BORE INTERSECTING THE RETAINING RECESS, THATIMPROVEMENT WHICH COMPRISES A BASICALLY CYLINDRICAL PLUNGER MOVABLEAXIALLY IN A CYLINDRICAL BORE, HAVING ONE WALL ADAPTED TO MATCHCOMPLEMENTALLY THE CYLINDRICAL WALL OF THE BORE AND HAVING AN OPPOSITEWALL FORMED AS A CYLINDER ON AN AXIS ANGLED TO THE AXIS OF SAID PLUNGERAND SAID BORE, SAID ANGLE INCREASING AWAY FROM THE BORE AND A